In patients with autoimmune diseases, anti-idiotypic antibodies directed
to nucleoprotein complexes, DNA, and enzymes that participate in nucleic
acid metabolism may be induced spontaneously by primary antigens and can
have characteristics of the primary antigen, including catalytic activity.

Subsequently, other abzymes able to hydrolyze proteins, DNA,
RNA, or polysaccharides have been found in the sera of patients with autoimmune
and also viral pathologies.

Further, we have discovered in the milk of
healthy human mothers antibodies that catalyze the hydrolysis of RNA, DNA,
nucleotides, and the phosphorylation of lipids and proteins.

The phenomenon
of catalysis by autoantibodies is extremely interesting and can potentially
be applied to many different objectives including new types of efficient
catalysts, evaluation of the functional roles of abzymes in innate and
adaptive immunity, and understanding of certain aspects of self-tolerance
and of the destructive responses in autoimmune diseases.In this review,
we collate methods for purifying and characterizing natural abzymes especially
those catalyzing DNA and RNA hydrolysis.

We also describe new methods that
we have developed to provide rigorous criteria that catalytic activity
is an intrinsic property of some antibodies.

Some major current themes
are discussed as well as potential applications of abzymes in scientific,
medical, and biotechnological fields.